The Present Application relates to a cooling device for diffusing heat from a heat generating element such as an electronic component and radiating the diffused heat to the outside, and the Present Application relates more specifically to a small cooling device with a superior thermal design.
Electronic devices, industrial equipment and automobiles all use elements and electronic components such as semiconductor integrated circuits, LED elements and power devices that generate a lot of heat. When the heat generated by these elements and electronic components is above a given temperature, the operation of these elements and components cannot be ensured and the heat has an adverse effect on other components and on the case. As a result, the performance of the electronic device or industrial equipment may deteriorate. In order to cool these heat generating elements, a heat sink or heat pipe is used.
Because of market demand for smaller and thinner electronic devices and industrial equipment, semiconductor integrated circuits have become even more integrated and electronic components have become even smaller. As the performance and processing power of these smaller electronic components has increased, the amount of heat generated by the heat generating elements has increased significantly. If the heat generating element is a semiconductor integrated circuit, light-emitting device or power device, the amount of heat generated by the small heat generating element is considerable.
When these heat generating elements are cooled by a heat sink, the cooling performance is inadequate. As a result, heat sinks have been replaced by heat pipes which cool heat generating elements by vaporizing and condensing a coolant sealed inside. When the amount of heat generated by the heat generating element is considerable, a very large heat pipe is needed to diffuse the heat. When the heat pipe plays a major role in diffusing heat and the amount of heat generated by a very small heat generating element is considerable, there is a significant size discrepancy between the heat generating element and the heat pipe, and the thermal diffusion is inadequate.
When a heat pipe is combined with a heat sink to diffuse heat, a very large heat pipe has to be stacked with an even larger heat sink for a small heat generating element. As a result, a cooling device with a heat pipe and a heat sink takes up more space in both the planar and height directions than the heat generating element.
Also, when a heat sink is combined with a heat pipe, a number of separate components has to be assembled. This means performance varies between completed cooling devices.
In order to solve this problem, a technology has been proposed in which a recess is formed in the bottom surface of a heat sink and a heat pipe is laid inside the recess. An example of this is disclosed in Japanese Patent Application No. 2002-64170.
A configuration was disclosed in the '170 Application in which a recess is formed in the bottom surface of a heat sink and a heat pipe is laid inside the recess. The purpose of this configuration is to reduce the mounting area heightwise. As a result, a comprehensive heat exhaust design for the heat generating element cannot be undertaken.